[DiapDealer]

My KindleImport plugin (based on KindleUnpack) will produce the following dc metatdata:

        if epub_version == "2":
            dc = '''<dc:identifier opf:scheme="AMAZON">%s</dc:identifier>''' % asin
        elif epub_version == "3":
            dc = '''<dc:identifier>urn:AMAZON:%s</dc:identifier>''' % asin

But that's a manual opt-in tweak only intended to provide seamless integration with Doitsu's Kindlegen plugin.

https://www.mobileread.com/forums/sh...&postcount=147

At the time of the change to the Kindlegen plugin, it was determined that the <dc:identifier>urn:AMAZON:%s</dc:identifier> was recognized by calibre. https://www.mobileread.com/forums/sh...2&postcount=73

But the vast majority of the time, KindleImport should be producing whatever the underlying KindleUnpack produces in this regard.